Name Description
BENCHMARK()Repeatedly execute an expression
CHARSET()Return the character set of the argument
COERCIBILITY()Return the collation coercibility value of the string argument
COLLATION()Return the collation of the string argument
CONNECTION_ID()Return the connection ID (thread ID) for the connection
CURRENT_USER(), CURRENT_USERReturn the username and hostname combination
DATABASE()Return the default (current) database name
FOUND_ROWS()For a SELECT with a LIMIT clause, the number of rows that would be returned were there no LIMIT clause
LAST_INSERT_ID()Value of the AUTOINCREMENT column for the last INSERT
ROW_COUNT()The number of rows updated
SCHEMA()A synonym for DATABASE()
SESSION_USER()Synonym for USER()
SYSTEM_USER()Synonym for USER()
USER()Return the current username and hostname
Quote: dev.mysql.com/doc/refman/5.1/en/index.html